1. Field of the Invention
The present invention relates to an apparatus for controlling generation of data cells, and more particularly, to an apparatus for controlling generation of ATM cells which are required to be generated from plural channel data within the respective bit rates assigned thereto.
2. Description of the Related Art
A protocol in an ATM layer of an ATM (Asynchronous Transfer Mode) network or an ATM LAN (Local Area Network) is simple in order to realize it by hardware circuits. Data are transmitted in a form of ATM cells having fixed data length (53 bytes), and cells are simply discarded when congestion of cells occurs in the network. Therefore, traffic control in a higher layer such as an AAL (ATM Adaptation Layer) is necessary to maintain quality of services in individual connections.
In the case of an AAL which adapts plural data terminals or a data network to the ATM, a bit rate of data transmitted in each data channel is assigned to each data channel, and generation of ATM cells of each data channel is controlled based on the assigned bit rate.
The bit rate control could be carried out in a CLAD (Cell Assembly/Disassembly) circuit provided corresponding to each data terminal. However, numerous control circuits would be required in the AAL which adapts numerous e.g. a thousand data terminals, if the bit rate control were carried out in the CLAD circuit provided corresponding to the data terminal.